لَّـكِنِ الرَّاسِخُونَ فِي الْعِلْمِ مِنْهُمْBut those among them who are well-grounded in knowledge...,firm in the religion and full of beneficial knowledge.We mentioned this subject when we explained Surah Al Imran.The Ayah;وَالْمُوْمِنُونَand the believers...,refers to the well-grounded in knowledge;يُوْمِنُونَ بِمَا أُنزِلَ إِلَيكَ وَمَا أُنزِلَ مِن قَبْلِكَbelieve in what has been sent down to you and what was sent down before you;Ibn Abbas said,"This Ayah was revealed concerning Abdullah bin Salam, Thalabah bin Sayah, Zayd bin Sa`yah and Asad bin Ubayd who embraced Islam and believed what Allah sent Muhammad with." Allah said,وَالْمُقِيمِينَ الصَّلَةَand those who perform the Salah,وَالْمُوْتُونَ الزَّكَاةَand give Zakah,This could be referring to the obligatory charity due on one's wealth and property, or those who purify themselves, or both.Allah knows best.وَالْمُوْمِنُونَ بِاللّهِ وَالْيَوْمِ الاخِرِand believe in Allah and in the Last Day,They believe that there is no deity worthy of worship except Allah, believe in Resurrection after death and the reward or punishment for the good or evil deeds.Allah's statement,أُوْلَـيِكَIt is they,those whom the Ayah described above.سَنُوْتِيهِمْ أَجْرًا عَظِيمًاTo whom We shall give a great reward.means Paradise